Testing the SF-36 in Parkinson's disease. Implications for reporting rating scale data.

Rating scales are increasingly the primary outcome measures in clinical trials. However, clinically meaningful interpretation of such outcomes requires that the scales used satisfy basic requirements (scaling assumptions) within the data. These are rarely tested. The SF-36 is the most widely used patient-reported rating scale. Its scaling assumptions have been challenged in neurological disorders but remain untested in Parkinson's disease (PD). We therefore tested these by analyzing SF-36 data from 202 PD patients (54% men; mean age 70) to determine if it was legitimate to report scores for the eight SF-36 scales and its two summary measures of physical and mental health, and if those scores were reliable and valid. Results supported generation of the eight SF-36 scale scores and their reliabilities were generally good (> or = 0.74 in all but one instance). However, we found limitations that question the meaningfulness of four scales and other limitations that restrict the ability of four scales to detect change in clinical trials (floor/ceiling effects, 19.6-46.2 %). The two SF-36 summary measures were not found to be valid indicators of physical and mental health. This study demonstrates important limitations of the SF-36 and provides the first evidence-based guidelines for its use in PD. The limitations of the SF-36 demonstrated here may explain some unexpected findings in previous studies. However, the main implication is a general one for the clinical research community regarding requirements for reporting rating scale endpoints. Specifically, investigators should routinely provide scale evaluations based on data from within major clinical trials.

Deep-brain stimulation in the subthalamic nuclei improves balance performance in patients with Parkinson's disease, when tested without anti-parkinsonian medication.

OBJECTIVE: To evaluate the effect of bilateral deep-brain stimulation (DBS) in the subthalamic nucleus (STN) on balance performance in patients with severe Parkinson's disease (PD), when tested without anti-parkinsonian medication. MATERIAL AND METHODS: Thirty-one patients (median age 65 years, range 50-77) were included. Assessments were made after 10-12 h withdrawal of medication, before and 6 and 12 months after surgery. Postoperative evaluations were performed with DBS on and off. Balance performance was evaluated with the Berg Balance Scale (BBS). Motor symptoms and postural stability (item 30) were assessed with the Unified Parkinson's Disease Rating Scale (UPDRS III). RESULTS: DBS in STN improved balance performance as well as postural stability and motor symptoms significantly (P

Neurosurgery for movement disorders.

Movement disorders have been treated neurosurgically since the 1930s. Current diagnoses for neurosurgical interventions are Parkinson's disease, essential tremor, multiple sclerosis, and some dystonic disorders such as idiopathic torsions dystonia. By using stereotactic image-guided techniques, targets can be chosen to treat different symptoms: the ventrointermediate nucleus of thalamus for tremor; the internal globus pallidus for dyskinesia, dystonia, rigidity, akinesia, and tremor; and the subthalamic nucleus for all cardinal symptoms in advanced Parkinson's disease, including drug-induced hyperkinesia (secondary to reduced drugs). The surgical approaches can be divided into three main groups: destructive (e.g., lesional surgery), reversible and adjustable (e.g., permanent electro-inhibition/stimulation), and reconstructive (e.g., fetal nerve cell transplantation). Reconstructive procedures, which are not discussed here, are still in the early developmental phase. All the methods have advantages and disadvantages; therefore, it is important that the right target and technique be chosen for each patient.